Sherlock, season 3, episode 3, review

His Last Vow, the final part of season three of BBC One's Sherlock, was the
best of the lot, says Serena Davies

So, Sherlock’s last, dark chapter in 2014 was the best of the lot. This wasn’t surprising. Its author Steven Moffat is the superior Sherlock writer;Mark Gatiss tends to over-complexity, Steve Thompson lacks pace. Moffat gets the wary dance between plot and character just right; rarely messing up the steps, never coming to a standstill. Thus after the adrenaline rush of New Year’s Day’s The Empty Hearse (Gatiss); the saggy middle of The Sign of Three (Thompson); came the fierce panache of last night’s His Last Vow.

For Sherlock he had found his true calling and become a reptile. As Magnussen, he licked one of his appalled victims. And in one sequence, excellent in its understatement, he repeatedly flicked Watson in the eye as if his finger were the tongue of a snake. If he’d chopped him up with a saw it couldn’t have been more horrid.

And – look away now if you don’t want to know it - Moffat also got to deliver the killer twist of the series. The twist about the killer: little Mary Morstan was actually an assassin. Her marrying John Watson was an attempt to turn over a new leaf. Maybe the rest of the universe saw this coming but I didn’t and the shock was all the sweeter because the drip feed of clues in the previous two episodes had been memorable. Particularly that little word ‘liar’ hovering over her face when Sherlock first met her.

Into this set up Moffat threw true romance (Watson’s forgiveness of Mary for her previous life); Sherlock being a crack addict; Sherlock getting a girlfriend; Sherlock being shot; Sherlock dying then coming back to life; Sherlock killing someone else – properly and like he meant it - and Moriarty. It was like Christmas for Sherlock fans. Indeed, Christmas was in there too. The episode belted along, was neatly structured, and boasted not just the one jaw-dropping surprise (outlined above) but a couple more narrative broadsides.

The programme has also managed to spin a storyline out across 24 months, with just a couple of episodes at either end to hold the tension. The mystery of how Holmes had faked his own death had viewers on tenterhooks two years ago; the fans feverishly concocting theories ever since. In acknowledgement of the hysteria, the makers delivered not one but three explanations in the New Year's Day episode. The entertaining, post-modern nods to the outside world continued in the second episode with its conceit of showing us Martin Freeman, as Watson, marrying his real-life partner, Amanda Abbington (to whom he isn’t married). We’ve also had Sherlock’s parents played by Cumberbatch’s actual mother and father.

Some carp that all these in-jokes are a distraction, that the show is just too pleased with itself. I don’t think it stops the carpers watching, since the show’s ratings have been around an enormous nine million an episode. Perhaps the programme has indeed become a little vain, rather a show-off. But then it would only be aping its central protagonist, and, despite his personality flaws, aren’t we all a little in love with Sherlock Holmes right now?